The present invention relates to a winding machine for winding up a traveling web that was produced on a paper making machine or on a similar web producing machine. In particular, the invention relates to the means that drives the web receiving cylinder to rotate.
Such winding machines have a pair of spaced apart, parallel primary levers that swing together and have a common center of swing that is generally slightly eccentric with respect to the axis of rotation of the carrying drum. If the primary levers are in a vertical orientation, so that the web receiving cylinder which is inserted in the forks of the primary levers is initially above the carrying drum at its upper vertex point, then there is a slight distance between the outer surface of the cylinder and the outer surface of the carrying drum. Due to the eccentricity, this distance gradually decreases during the swinging of the primary levers in the direction of travel of the web so that after a few angular degrees the outer surfaces of the carrying drum and the cylinder contact each other. Thereafter, the cylinder or the new web package, i.e. the "reel", produced on the cylinder is frictionally driven. Frequently, the cylinder has also been brought to the correct speed of rotation by a special starting device prior to this. Along the primary path, which is around the carrying drum, the resultant reel is pressed with greater or lesser force against the outer surface of the carrying drum in order to obtain a given linear pressure and thus a certain hardness of the wound web package or reel. The linear pressure is also maintained along the secondary path of the cylinder by a corresponding pressing by means of secondary levers.
Such winding machines, also known as "Pope rollers" generally form the end section of a paper making machine and operate to bring the web of paper obtained there into reel form. However, they are also used in order to rewind a web package which had already been finished in order to produce a new web package.
In all cases, the web package should have specific properties, particularly with respect to the hardness of the reel. The hardness of the reel should decrease from a certain initial value to a final value. The decrease should, as far as possible, be uniform from the first or inner layer to the last or outer layer. It should have a specific gradient, i.e. not be too strong and not too weak. The variation in the hardness of the reel should not show sudden changes anywhere, for instance, it should not show a sudden drop.
All of the foregoing objectives have not been achieved with the prior art. Winding machines of known construction instead produce, for instance, reels in which the center is extremely hard while toward the end, i.e. approximately at 4/5ths of the diameter of the reel, there is a great decline in the hardness of the winding. This causes the first part and, therefore, the extremely hard center, to be unusable since the web is overstressed in this region and bursts, so that this part must be thrown away as waste. In the outer end region, in which the reel has not been wound sufficiently hard, there is a lateral displacement of the layers relative to each other, so that the ends of the finished reel appear uneven and the edges of the web can be easily damaged.
In general, it is desirable to pass over the primary path of the cylinder as rapidly as possible. The duration of the stay of the reel in the primary path of the cylinder is thus small as compared with the duration of the stay in the secondary path. Accordingly, only a few centimeters of the diameter of the reel are produced over the primary path. Nevertheless, these first centimeters are important. A poorly constructed center having too little or too much hardness, for example, does not permit a dependable construction of the rest of the reel. The problem is particularly serious in the case of pressure sensitive papers, for instance, no carbon papers, for which narrow limits are set for the pressing of a cylinder which is having a reel produced thereon, against the outer surface of the carrying drum.